New Industry Products

Diodes Incorporated Introduces a New Controller for P-Channel Enhancement Mode MOSFETs

February 23, 2022 by Gary Elinoff

The controller, when paired with a P-channel MOSFET configured as an ideal diode, provides the high-side rail isolation needed for reverse current blocking.

Diodes Incorporated has engineered its new DZDH0401DW to provide greater power efficiency in a simple, compact design. The controller is cased in an SOT63 package measuring just 2.1 x 2.15 x 1 mm, and can reliably block reverse current up to 40 V.

A typical DZDH0401DW configuration. Image used courtesy of Diodes Incorporated


As illustrated in the schematic, the DZDH0401DW enables a streamlined system. Here, it is accompanied by a single MOSFET and just two resistors, making it suitable for space-constrained designs. 


Basic Operation, In Depth

The DZDH0401DW operates as a differential amplifier, comparing VOUT to VIN. It is designed to control a P-channel enhancement mode FET, a type of FET that is normally open — no conduction.

If in typical configuration the measured differential between VIN and VOUT is greater than ~34 mV, the controller will drive a reduction in voltage across RBIAS and the P-channel FET will turn on, conducting with minimal current losses. If the differential falls below that threshold, the controller will instead drive a voltage rise across VBIAS, and the FET will turn off. This effectively isolates VIN from VOUT.


Improvement over Diode-based Solutions

Diode rectifiers typically feature a voltage drop of 0.55 volts. At 3 A, power dissipation is 0.55 V x 3 A = 1.65 watts. The DZDH0401DW companion FET touted by Diodes Incorporated, the DMP4047LFDE, has an RDS(ON) of 33 mΩ. At 3 A, I2R is 3 x 3 x .033, or 0.297 W.


The DMP4047LFDE. Image used courtesy of Digi-Key


At 3 amps of forward power, that difference represents significant energy savings. Crucially, it also indicates that less waste heat will be generated. 


Major Specifications of the DZDH0401DW

Absolute Maximums

  • Max input voltage: 40 V 
  • Peak bias current: -300 mA 
  • Max reverse voltage protection: 50 V 

Thermal Characteristics

  • Power dissipation: 300 mW
  • Thermal resistance, junction to ambient: 424 ℃/W
  • Thermal resistance, junction to case: 111 ℃/W


Maximum power dissipation persists up to 25 ℃. Beyond that point, power dissipation decreases linearly to zero at 150 ℃.



  • Battery discharge protection
  • High-side disconnect switches
  • OR-ing rectifiers used in data centers' hot-swappable and N+1 redundancy power supplies 
  • Battery discharge protection 
  • Cordless power tools
  • Emergency lighting systems 

Physical Considerations

  • The DZDH0401DW operates over a temperature range of -65 to +150℃
  • Moisture sensitivity at level 1 as per J-STD-020 
  • UL flammability classification rating is 94 V-0 


Diodes Incorporated can supply the DZDH0401DW in versions qualified to AEC-Q100/101/200, and that are PPAP-capable, if needed. The company can also manufacture the device in IATF 16949-certified facilities.


Environmental Notes 

  • Lead-free & fully RoHS-compliant
  • Halogen and antimony-free 


Feature image used courtesy of Diodes Incorporated